SQLAlchemy Polymorphism in ORMAR #825

Hi, I'm currently missing some SQLAlchemy functionality for a project I'm currently working on.

This functionality is polymorphism. SQLAlchemy provides the ability to create inheritance between classes by defining polymorphism using a type field. Does this option exist in Ormar or will it be planet in the short term? it would be very useful.

Here the documentation: https://docs.sqlalchemy.org/en/14/orm/inheritance.html